An investigation of the influence of some experimental parameters on thermochromatographic separations has been carried out.
It is shown that the position of the deposition zone depends on separation time, purity of the inert gas, and on type and
amount of the chlorinating agent. The gas flow rate and the amount of the transported compounds have no influence within the
limits of experimental conditions. From the experimental results it can be concluded that in some cases the deposited compounds
react with the surface or with the excess gas.
Authors:Greg Albright, Mohammed Farid, and Said Al-Hallaj
The use of phase change materials (PCMs) in thermal storage is not a new concept, but engineers are continually finding new
ways to utilize them in a wide range of applications. A PCM takes advantage of high latent heat in the phase change process
to store large amounts of heat while undergoing only a small change in temperature. This property makes PCMs suitable for
thermal storage purposes in a wide range of engineering applications. Due to the nature of these applications, it is vital
to have a precise knowledge of the thermal characteristics of any PCM. Unfortunately, due to the low thermal conductivities
and high latent heats found in PCMs, current measuring tools such as differential scanning calorimetry, provide inconsistent
results. This paper conjectures that these errors come from the effects of low thermal diffusivity samples as well as improper
data analysis methods.
to the product of the entropy change, Δ S , and the temperaturegradient, Δ T , which is the difference between the thermodynamic temperaturegradient (associated with transformation) and the heat-imposed gradient at the reaction interface as a
Authors:L. Vega, A. Torres, W. Hoffmann, and I. Lamprecht
temperature organs or gradient chambers. As such a temperaturegradient chamber (TGC) the authors built two wooden boxes, which were placed one above the other. The lower chamber was divided into two compartments by a wooden wall. The first compartment housed
Authors:Kai Zheng Fang, Dao Bin Mu, Shi Chen, Feng Wu, and Xiao Jun Zeng
charging rate increases. Meanwhile, the temperaturegradient in axial direction ( z ) increases remarkably with charging rate increase. The higher the charging rate, the larger the temperaturegradient is. The maximum surface temperature is up to 60.99 °C
Authors:Mark S. Romano, Sanjeev Gambhir, Joselito M. Razal, Adrian Gestos, Gordon G. Wallace, and Jun Chen
electrolyte, i.e. for systems using reversible redox couples, is given by , where K is the thermal conductivity of the electrolyte, A is the cross sectional area of each electrode and is the temperaturegradient across the distance between the two
Starting from tabulated thermodynamic data of stable compounds in the Mo−O−Cl system, phase diagrams for the Mo−O−Cl system
were developed on the basis of GIBBS' phase law by means of thermodynamic calculations. The behaviour of molybdenum trioxide
in a temperature gradient tube was investigated experimentally under chlorinating conditions, using99Mo as indicator. The thermochromatografically separated compounds were characterized by their deposition temperature in the
temperature gradient tube and by an activation analytical determination of their Mo/Cl ratio. The experimental results were
compared with the calculated phase diagram.
Authors:T. Kousksou, A. Jamil, Y. Zeraouli, and J. Dumas
Differential scanning calorimetry (DSC) is applied to analyse the process of ice melting. Experimental results were compared
to those obtained by a numerical simulation in which a conventional enthalpy formulation was applied. The effects of various
parameters on the kinetics of transformations and therefore the shape of curves has been analysed and the importance of temperature
gradients inside the sample evaluated.
An application of the temperature gradient tube method is described, which has allowed to chemically separate the elements,
Be, Ca, Sc, Ti, V, Cr, Mn produced in an iron target irradiated by high energy protons, without noticeable contamination by
natural impurities. It is suggested that this method could be useful in other works on small quantities of stable isotopes.